1. Field of the Invention
The present invention generally relates to the design of magnetic retrieval devices used for cleaning the interior of tubular members.
2. Description of the Related Art
Metallic debris accumulates within wellbores and other tubular members during production of subterranean fluids, such as hydrocarbon fluids. This metallic debris typically includes tiny metal shavings and cuttings. These shavings and cuttings result from numerous frictional operations that might occur within the wellbore or tubular, including the cutting of sidetracking windows, milling, drilling through stuck devices and objects, as well as general operations that cause metal-to-metal scraping to occur.
Devices used for the removal of metallic debris by magnets are described, for example, in U.S. Pat. No. 7,515,299, U.S. Pat. No. 7,219,724 and U.S. Pat. No. 7,137,449.